I’m taking some nutrition courses these days, and as part of my coursework, I’ve been learning about food availability or food disappearance data. These are data that reflect a country’s total annual food production, imports, and initial stock of food, subtracting out exports, non-food uses of these items, and end-point stockpiles. As such, they overestimate what people eat (because they include in the total food that was spoiled and thrown out, for example), but give a rough idea of people’s food consumption and trends over time. These data have been reliably collected in the U.S. for more than a century (although not necessarily for all foods), so they provide an interesting snapshot of what we are eating. The below information I collected for a class assignment, but I thought it was so interesting it deserved a wider audience and am sharing it here as well.

Since food availability data are available for many foods going back decades, we can observe whether changes in food consumption in the U.S. over time map onto changes in other health indicators. My interest here of course is in obesity, and what people breathlessly call the “obesity epidemic.”

The green-gray area at the bottom of the graph is the percentage of U.S. adults who were classified as overweight in that year; the dark green is the percentage obese, and the gray at the top is the percentage of extremely obese people. I’m a little confused by the graph in that BMI definitions for overweight, obese, etc., changed in the mid-1990s, and I don’t know whether this graph adjusts for that or uses the earlier or later definitions. But for now let’s just assume that the definition of these categories remained constant over time.

What’s interesting about this graph is first of all that there is no epidemic of overweight. The percentage of people in the overweight category has stayed roughly steady over time. (That is interesting in and of itself. Why don’t *both* overweight and obesity increase during this time?) But they don’t: Only obesity and extreme obesity have increased. It’s also interesting to observe that that change happened suddenly. Somewhere between the late 1970s and 2000 is when essentially all of the change occurred, and then it leveled off.

If you believe diet causes obesity (and I’m far from convinced on this point, but many people do believe this), then you should be interested in what on earth might have dramatically changed in Americans’ diets between 1970 and 2000 to explain the change. The change — whatever it was — should have happened at or just before that time, and then leveled off to produce a pattern similar to what we see on the graph.

Food disappearance data should be one of the best sources to examine this question.

Before we look at the data, though: Take a guess. What do you think has changed in Americans’ diets since 1970 that explains the increase in obesity during that time? Really, write it down. Keep yourself honest. Now, let’s take a look:

This article (http://ajcn.nutrition.org/content/91/5/1530S.full; Barnard, 2010) provides some useful tables summarizing food availability data since 1909. If you want to explain the “obesity epidemic” using diet, you should be looking for foods that saw big increases or decreases between 1970 and 2007.
Here’s one relevant table from that article:

TABLE 1

Availability of major food commodities in the United States, 1909–20071

In looking at the table, there were reasonably big increases in the following foods between 1970 and 2007: poultry, low fat and skim milk, cheese, salad and cooking oils, whole fruit and fruit juices, vegetables (mainly fresh and frozen), grains, corn syrup, and non-milk beverages, especially soda, water, and beer and wine. (The article notes something the table doesn’t — most of that increase in soda is an increase in diet soda, NOT sweetened soda).

Big decreases happened with milk, red meat, eggs, and sugar.

So, what do you make of that? Which of those changes do you think most plausibly relate to the change in obesity, and why? (Or do you think none of these factors explain it, and why?)

My own take is that either these changes do not explain the increase in obesity at all (they seem to be mostly relatively small changes), or if a change is partially responsible, then these are my votes for which foods are plausible:

The increase in poultry might be responsible, if antibiotic residues in poultry are causing changes in the human gut microbiome (e.g., see Riley, Raphael & Faerstein, 2013)

Perhaps high fructose corn syrup

Perhaps diet soda, particularly since diet soda consumption may be a marker for dietary restriction, which may lead to weight gain

We know that non-weight-loss, body acceptance approaches to health (sometimes called Health At Every Size) can work in terms of helping people at a range of weights achieve better markers of physical health. For example, several randomized controlled trials have shown improvements in cholesterol and blood pressure in “overweight” and “obese” women using these approaches. But how?

Generally these approaches don’t cause weight loss — they’re not designed to cause weight loss, and the focus is on body and self acceptance. One answer may lie in the lifestyle improvements women in these studies made. Various studies found that they became more active, and/or ate a higher quality diet, and/or engaged in less binge eating. So maybe it’s simply those positive changes that caused the physical improvements.

Perhaps connecting to a community of other higher-weight folks who are practicing body acceptance, standing up to size-based discrimination, and challenging their internalized anti-fat bias is what leads to some of these improvements, not just better eating and exercise.

In case you need some models for some aspect of your own life that feels impossible to you now, I’m starting a People Doing Things series on this blog to help you visualize or locate people who look like you doing things you’d like to be doing. I’m aiming to illustrate human diversity, but each post — of course — will not be comprehensive. Pingbacks are permitted on this blog, so feel free to link here if you have an example on your own blog of People Doing Things, and I will update the post to show your suggestions!

To begin with, let’s look at photos, videos, and blogs of people dancing!

That’s Ragen Chastain dancing, by the way. You can read her dance blog here.

So, you’re with me thus far: Diets don’t work to help people lose weight. “Healthy lifestyle change” doesn’t help people lose weight (nor is it clear that it helps people get healthy, actually, but more on that later). Your failure to feel better by changing your body shape or size may be beginning to make sense in context: You can’t do it, because apparently it can’t be done.

Let’s look at that idea a bit more closely. To do that, we start with your BMI, your Body Mass Index. The BMI is a measure of body size that is less crude than a simple weight measurement in that it corrects for expected variation in weight due to height. (I said it was less crude. I did not say it was elegant.) Research done on obesity often uses BMI as its outcome measure.

is in better health and can expect to outlive apparently”underweight” Angelina Jolie:

A quick note: In looking at these photos, I encourage you to check your body policing urges at the door. I am not claiming that any of these prominent women is or is not healthy, or does or does not lead a “healthy lifestyle” (whatever that means), as I don’t have any data to address those questions and am not inclined to police the private, personal behavior of individuals even if I did. I set these pictures side-by-side as vivid illustrations to encourage you to challenge your stereotypes about body shape and health and marvel about the inaccuracy of the messages you might have received about that. They’re not here so you can trade one set of unrealistic expectation about what is “healthy” for another.

Of course, even Weight Watchers claims that “diets don’t work; weight watchers does.” Diets may not work, you might be thinking, but what about “healthy eating” or “healthy lifestyle change”? Surely if you eat right you will lose weight, right?

Not so fast. The Women’s Health Initiative Dietary Modification Study was the largest, most extensive, experimental study of “healthy eating” ever conducted. More than 48,000 older women (ages 50-79) were randomly assigned to either eat their usual diet, or eat a low-fat, high fiber, diet with lots of vegetables, fruits, and whole grains — the essence of what most people think of as “healthy eating.”(They chose older women because they wanted to be sure there would be enough incidence of disease among the participants to detect differences between the groups after several years of follow up.)

The women in the intervention group had intensive, state-of-the-art support to maintain their diets — an intensive initial group treatment led by nutritionists, followed by a long-term maintenance intervention group that met regularly over the course of the study, individual counseling, and personalized feedback on their dietary targets and progress. They ate this diet and continued in the intervention program (and were compared to their control-group counterparts) for an average of 8 years of follow up.

And despite maintaining a restricted diet for 8 years — at follow up, they were eating an average of 361.4 kcal/day less than they had been eating at baseline — these women lost a total of about one pound, on average, compared to the women who ate as they pleased.

These women successfully changed their eating lifestyles for 8 years: more fruits and vegetables, more whole grains, less fat, less calories. Classes, nutrition groups, hearing feedback about how they were doing. (“Couldn’t you cut out the chocolate, Ann-Marie?”) Yet they didn’t do better in terms of cardiovascular health, or cancer. They lost only a pound, for 8 years of effort. Would that be worth it to you?

So, did you figure out why? What are the reasons you have engaged in a struggle with your body? Do you want to feel better about yourself? Do you hope to feel more confident, less self-conscious, sexier, more accomplished, more energetic, more optimistic, happier?

So: How’s that working for you? How far have your efforts brought you to these positive feelings? Maybe you already know that they have not in fact brought you closer either to solving the problem or achieving happiness — that in fact your problem has become larger and your self-hatred and unhappiness more intense.

But that’s only because these strategies haven’t worked, right?

If only you could have the body you dream of…

If only you were thin…

Then, then you would be happy.

You may not know how to get there, but you know that if somehow you could, your life would begin.

But consider the situation of people with anorexia. People with anorexia, by definition, have been successful at achieving thinness. One stringent definition of Anorexia Nervosa requires sufferers to have a BMI of 17.5 or less.

A BMI of 17.5 or less is not necessarily what you may think of as “emaciated.”